Vn] INSECTICIDES AND FUNGICIDES 77 



acid. Titrate this neutral solution with approximately N/20 iodin, 3 ^C), using a 

 few drops of starch solution as indicator. From the number of cc. of iodin solu- 

 tion used, calculate the thiosulphate sulphur present. 



73 SULPHATE SULPHUR.— OFFICIAL. 



To the solution from the determination in 72, add 2 or 3 drops of hydrochloric 

 acid, precipitate in the cold with 10% barium chlorid solution, allow to stand over- 

 night, filter, calculate the sulphur from the weight of barium sulphate and report 

 as sulphate sulphur. 



74 TOTAL LIME.— OFFICIAL. 



To 25 cc. of the solution, prepared as under 68, add 10 cc. of concentrated hydro- 

 chloric acid, evaporate to dryness on the steam bath, treat with water and a little 

 hydrochloric acid, warm until all the calcium chlorid is dissolved, and filter from sul- 

 phur and any silica that may be present. O.xidize the filtrate by boiling with a 

 little concentrated nitric acid, make ammoniacal, filter from iron and aluminium 

 if present, heat to boiling and precipitate the calcium with ammonium oxalate so- 

 lution. Filter, wash and ignite over a blast lamp to constant weight; weigh the 

 residue as calcium o.xid. 



BIBLIOGRAPHY. 



1 J. Ind. Eng. Chem., 1916, 8: 327. 



' Ibid., 1909, 1: 208. 



» J. Assoc. Official Agr. Chemists, 1915, 1: 436, 446. 



« J. Am. Chem. Soc, 1901, 23: 115. 



» Ibid., 1902, 24: 1082. 



« Ibid., 1900, 22: 802. 



' U. S. Bur. Chem. Bull. 122, p. 106. 



» Am. J. Sci., 1890. 3rd ser., 40: 66. 



' U. S. Bur. Chem. Bull. 137, p. 40. 

 '"Ibid., 105, p. 166. 

 " Ibid., p. 167. 



^^ Fresenius. Quantitative Chemical Analysis. Revised and amplified transla- 

 tion of the 6th German ed., 2 : 1180; U. S. Geol. Surv, Bull. 422, p. 179. 

 '^ Sutton. Volumetric Analysis. 10th ed., 1911, p. 207. 

 i< Ibid., 9th ed., rev., p. 201. 



1^ Lewkowitsch. Chemical Technology and Analysis of Oils, Fats and Waxes. 5th 

 ed., 1915, 3: -348. 

 '«Ibid., 346. 



'^ Sutton. Volumetric Analysis. 10th ed., 1911, p. 61. 

 >« U. S. Bur. Animal Industry, Bull. 133. 



I' Ber., 1898, 31: 2979; J. Am. Chem. Soc, 1905, 27: 1183; U. S. Bur. Chem. Bull. 

 99, p. 30; 132, p. 49; 137, p. 47. 



" Z. anal. Chem., 1897, 36: 18; U. S. Bur. Chem. Bull. 132, p. 49. 

 " J. Assoc. Official Agr. Chemists, 1915, 1 : 76. 

 " J. Am. Chem. Soc, 1911, 33: 844. 

 » J. Soc. Chem. Ind., 1912, 31: 369. 



